The ability to maintain a constant TCP/IP connection during travel of a mobile terminal provides an enhanced user web browsing session. For example, a persistent connection ensures that a user may not have to login into a network multiple times during travel of a mobile terminal, e.g., an airplane, land vehicle, maritime ship etc. During a flight, an airplane network receiver can receive network data from multiple satellite spot beams. In conventional systems, satellites broadcasts multiple spot beams to mobile terminals to establish network connectivity. However, conventional systems lack the capability of maintaining end to end connectivity throughout movement of the terminal across different spot beams. More specifically, a TCP connection could be terminated each time an airplane moved from one satellite spot beam to another. As a result, interactive sessions between devices in use on an airplane and terrestrial servers, which are both connected via a common satellite, would be terminated. As an example, if a user is logged into a web site during the transition of the airplane receiver from one satellite spot beam to another, the user's connection will be terminated and will be required to reconnect.
Modern satellite systems have spot beams that are relatively small in diameter. Accordingly, mobile terminals travelling at high rates of speed with respect to the satellite can transition across an entire spot beam in a matter of minutes. A user would then be required re-login every few minutes, as the mobile terminal travels to its destination. Additionally, conventional satellite systems require temporary suspension of data packet transmission during the handover process between multiple satellite spot beams. This operation is inherently inefficient, as data packets are retransmitted to account for the time period that a physical satellite link being unavailable.
Accordingly, it is desired to develop a system that can prevent the loss of end to end connectivity as a terminal transitions from one satellite spot beam to another. Additionally, there is also a desire to intelligently select amongst multiple available satellite spot beams in a mobile terminal communication system. It would be beneficial to allow terminal users to continuously interact with a web location, as the terminal transitions from one spot beam to another, without having to re-login each time. Furthermore, it is advantageous to have a system that prevents loss of data packets during handover, as handover of a terminal occurs from one satellite spot beam to another.
As a mobile terminal moves out of the coverage area of one satellite, it may also be desired to transition from one satellite to another. Additionally, it would be advantageous to have a system in which a mobile terminal can efficiently select an appropriate satellite spot beam with a goal of minimizing unnecessary handovers as the mobile terminal travels. Accordingly, a beneficial design would allow for the mobile terminal to select the best possible satellite data beam based on an expected travel path, continually evaluate adjacent candidate beams and select an appropriate beam at the appropriate time, and prevent unnecessary switching between multiple satellite beams when traveling through an overlap of multiple satellite data beams.